Energy experts will explain the implications of California's power problems for the commercial real estate industry at a forum and exhibition presented by the Los Angeles and Orange county chapters of the Building Owners and Managers Assn. from 7:30 a.m. to 5 p.m. Friday at the Westin Bonaventure Hotel, 404 S. Figueroa St., Los Angeles.

Sinking demand for new office space in Orange County appears to have bottomed out, reports Robert Dunham, president of Newport Economics Group. But demand for new office space for all of 1992 is expected to total less than 1 million square feet, which would be the third annual decline in a row from a peak of 4 million square feet in 1989. That makes the situation worse than in the 1974-75 and 1981-82 recessions, Dunham said.

Southern California's recession-weary commercial real estate market is slowly mending, analysts say, with vacancy rates inching downward and rents beginning to stabilize after a long plunge. Sales of office buildings are also picking up as lenders slash prices to unload foreclosed properties and out-of-state investors look west for returns that are sometimes twice the national average.